Hybrid materials including both metals and ceramics have traditionally been difficult to form and have also been plagued with durability problems. Many of these problems result from difficulties in filling void space within ceramics with a metal and with stable bonding between the metal and the ceramic.
Some such metal/ceramic hybrid materials for use in dentistry are described in U.S. Pat. No. 5,621,035. Specifically, the '035 patent describes filler compositions and ceramic enhanced dental materials. In one embodiment, the filler composition and the ceramic dental restorative material are comprised of about 22% by weight alumina, about 78% by weight silica, about 2% by weight silicon carbide, and about 2.85% by weight boron nitride with less than 1% cristobalite contamination. This material is porous and may be used in combination with metal amalgams.
Another porous ceramic material for use in dentistry is described in U.S. Pat. No. 5,951,295. The '295 Patent describes ceramic fused fiber enhanced dental materials, such as materials comprising from about 1% to about 50% by weight alumina, from about 50% to about 98% silica, and from about 1% to about 5% by weight boron.
Another similar ceramic is also described in U.S. Pat. No. 5,964,745 which describes an implantable system for bone or vascular tissue. The system comprises porous, linked fibrous biomaterial manufactured from nonwoven, randomly-oriented fibers linked together using a fusion source at a plurality of cross-points into a porous structure, the biomaterial having a plurality of voids of a predetermined mean void size effective for stimulating angiogenesis in said biomaterial from the tissue or bone.
Yet another porous ceramic material has been described in Yasukawa et al. in U.S. Pat. Nos. 5,629,186 and 5,780,281. A composite was prepared from silica and/or alumina fibers with added boron nitride.
Although attempts have been made to combine metals with ceramics, hybrid materials able to capitalize on the beneficial properties of both ceramics and metals still require additional development.